Clarify optional-shape practices

No effects were observed on Make-managed files.

Signed-off-by: Alex Nelson <alexander.nelson@nist.gov>

Author: ajnelson-nist

CONTRIBUTE.md

@@ -20,7 +20,7 @@ To create a new profile repository for the ontology with short name `Foo`, we su
    1. Addressing the "TODOs" in [`dependencies/Makefile`](dependencies/Makefile)
    1. Updating the TSV files under [`etc/`](etc/).  This is to support local-file editing with some ontology tooling (developed for [UCO Issue 449](https://github.com/ucoProject/UCO/issues/449)).  [These lines](https://github.com/ucoProject/UCO/blob/1.2.0/src/create-catalog-v001.xml.py#L68-L77) describe the file formats.
    1. Renaming the [ontology file under `/ontology`](ontology/uco-example.ttl), and updating its contents.
-   1. Renaming the [shapes file under `/shapes`](shapes/sh-uco-example.ttl), and updating its contents.
+   1. Renaming the [shapes file under `/shapes`](shapes/sh-uco-example.ttl), and updating its contents.  If the profile does not require shapes, the directory `shapes` can be removed.
    1. Updating the [exemplars file under `/tests`](tests/exemplars.ttl) to use all classes mapped in the profile ontology.
    1. After all of the above edits are completed, running `make check` from the top source directory should confirm Turtle files are normalized and unit tests pass.
 1. Push the updated profile to a new repository.

Makefile

@@ -104,10 +104,15 @@ all-ontology: \
 	$(MAKE) \
 	  --directory ontology
 
+# NOTE: For profiles that don't include shapes, the $(top_srcdir)/shapes
+# directory might be missing.  Checking for its existence first relieves
+# each profile of needing to modify the top Makefile when removing
+# shapes.
 all-shapes: \
   all-dependencies
-	$(MAKE) \
-	  --directory shapes
+	test ! -d shapes \
+	  || $(MAKE) \
+	    --directory shapes
 
 check: \
   .venv-pre-commit/var/.pre-commit-built.log \
@@ -140,11 +145,16 @@ check-ontology: \
 	  --directory ontology \
 	  check
 
+# NOTE: For profiles that don't include shapes, the $(top_srcdir)/shapes
+# directory might be missing.  Checking for its existence first relieves
+# each profile of needing to modify the top Makefile when removing
+# shapes.
 check-shapes: \
   all-shapes
-	$(MAKE) \
-	  --directory shapes \
-	  check
+	test ! -d shapes \
+	  || $(MAKE) \
+	    --directory shapes \
+	    check
 
 # This target's dependencies potentially modify the working directory's
 # Git state, so it is intentionally not a dependency of check.